%0 Journal Article %A ZHANG Yang %A LIU Qin-Huo %T Sensitivity Analysis of Large Scale Radiosity-Graphics Model and the Application on the Forest of Qilian Mountain %D 2009 %R 10.11867/j.issn.1001-8166.2009.07.0834 %J Advances in Earth Science %P 834-842 %V 24 %N 7 %X

Radiosity-Graphics Model(RGM)is mainly used to compute the Bi-directional reflectance distribution function (BRDF),which is suitable for small-scale scenes such as farmland, lawn or homogeneous forest. Large Scale RGM (LRGM) can be applied to simulate large-scale forest scene over complex topographic surfaces based on scene-dividing method. It can also save computing time. In this paper, sensitivity analysis of LRGM was carried out firstly, concerning different terrain conditions and different sub scene numbers. The results illustrate: ①BRDF is influenced by terrain, in back observation direction the terrain can strengthen the BRDF. In forward observation direction the terrain can weaken the BRDF; ②The sub scene number is not so sensitive to the BRDF. For example, the deviation is no more than 0.007; Secondly, Dayekou forest region in the Heihe River Basin was chosen as our study area, and the data including DEM, tree structure parameters and component spectral were used to simulate the BRDF of the scene by LRGM model. Then, the LRGM simulation result was validated with the ASTER data. The mean absolute error is no more than 0.0382. The result indicates that the LRGM can simulate the BRDF on a large scale well.

%U http://www.adearth.ac.cn/EN/10.11867/j.issn.1001-8166.2009.07.0834